Magnetic back-up rolls for roller levelers



R. T. TODD MAGNETIC BACK-UP ROLLS FOR ROLLER LEVELERS Filed July 2, 1956 Jamo 2S, E95

INVENTOR BY RUSSELL T To on W W ATTORNEY hired brutes MAGNETIC BACK-UP ROLLS FOR RULLER LEVELERS Application July 2, 1956, Serial No. 595,397

9 Claims. (Cl. 153-107) This invention relates in general to the art of leveling metal sheets and strip and more particularly to certain speciiic improvements in apparatus for accomplishing the leveling of metal sheets and strip, which apparatus is commonly referred to by the term roller leveler. As will be well understood in the art, the roller leveler consists essentially of a lower bank of leveling rolls, and an upper bank or set of similar rolls, which have identical spacing as the lower rolls but, which are offset horizontally therefrom, to be positioned intermediate the vertical projections of the lower rolls. In addition, the plane of the lower faces of the upper rolls is located below the plane defined by the upper surfaces of the lower set f rolls so that stock fed therethrough is caused to travel in a sinuous path around the outer contours of the rolls.

Experience has shown that the quality of smoothness and evenness obtained by this process is dependent upon the severity of the sinuous path taken by the metal. Rolls of small diameter have therefore been found to be most effective for this type of process. Small rolls are further advantageous in that a greater number of bending cycles may be made in a given linear distance than with rolls of larger diameter.

Because, however, a more acute bend requires a force of greater magnitude, problems are encountered in preventing undue stressing of the working rolls. For this reason it is a common expedient to provide either a single or a plurality of back-up rolls, which afford added rigidity and strength to the apparatus. These back-up rolls alleviate the problem of the bending of the Working rolls under load when leveling metal strip as is readily apparent.

However, when small diametered working rolls are utilized for leveling strip or sheets of great width, another deection problem concerning the upper working rolls is evidenced. When the roller leveler is idle, the upper working rolls sag in the middle of their length away from the upper back-up rolls, due to their own weight. This sagging of the upper working rolls creates several problems in the loading of an end of a piece of sheet or strip to be worked as the center portion of the roller leveler is usually partially blocked by the sagging upper rolls. In addition, the upper working rolls sag away from at least the central portion of the upper backup rolls, and this means when strip is started through the apparatus, the back-up rolls are not rotating and must be accelerated to the synchronous speed of the sheet or strip as the working rolls are forced thereagainst when leveling operations are started. This causes skidding and slipping between the working and back-up rolls which tends to pit and scuif the working rolls thus, in a short time, resulting in an inferior, and in many cases, a cornpletely unacceptable nal product. Also, when exceptionally wide and small diametered working rolls are utilized in roller levellers which are operated at high speed the upper working rolls tend to wobblef This is best explained by reference to normal operations wherein the tet rolls are driven at relatively low speeds and the axis of any individual upper working roll is at all times along a straight line. However, at high speeds, as for example when the strip being worked is traveling at 600 feet per minute, the axis of the upper working roll tends to move from the straight line thereby causing the roll to wobble. This effect is more noticeable near the unsupported center portions of the upper working rolls and is undesirable since the rolls mark and mar the stock moving through the leveller. Highly nished stock, such as thin stainless steel strip, is especially acceptable to this type of damage.

The above described conditions have somewhat limited the application of roller leveller apparatus in working strips or sheets of great width and have limited the realization of the inherent eiciencies associated with such mechanism. These conditions are especially noticeable when a roller leveller is operated at high speeds in levelling metal sheets or strip of great width. Further, when such equipment is used in a continuous process line, any slow-down of the roller leveller for loading means that the speed of other mechanisms in the process line must be curtailed. This is both expensive and time consuming as is readily apparent.

It is therefore the primary object of the present invention to provide an improved roller leveller wherein the downward bending of the upper working rolls under their own weight is substantially eliminated thereby resulting in more versatile and useful apparatus. In accomplishing this end the problems discussed above are substantially and effectively mitigated.

Yet another object of the present invention is to provide an improved roller leveller having the characteristics outlined above wherein the arrangement for holding the upper working roll against deflection is of the utmost simplicity in construction and manufacture. In the illustrated embodiment this is accomplished by providing the center of the back-up roll assembly with magnetic means to prevent the downward deflection of the working rolls.

These as well as other objects and advantages of the invention will become readily apparent upon further consideration of the following detailed specification and accompanying drawing wherein is disclosed a preferred embodiment of the invention.

In the drawing:

Figure l is a side elevation of a roller leveller constructed in accordance with the teachings of the present invention;

Figure 2 is an end sectional view taken along the section line II-II of Figure l Figure 3 is a side view of the magnetic back-up roll used in the apparatus of Figure l; and

Figure 4 is an end elevation of the apparatus depicted in Figure 3.

In accordance with usual practice, the roller leveller illustrated in the drawing comprises a set of lower working rolls 1li of small diameter and a like set of upper working rolls 1l with the upper and lower sets of rolls being offset horizontally from each other to define a sinuous path of strip travel through the roller leveller. These sets of rolls, 1t) and 11, are journalled in a housing 12 which sits on a suitable foundation, for example, on the iioor of a plant where the strip or sheet material is being worked. The arrangement of the rolls 10 and 11 is such that a sinuous strip pass line 14 is formed with the strip traveling through the working rolls as shown in Figure 2 of the drawing.

The strip enters a guide 15, passes through rubber covered pinch rolls 16 and 17 at the entrance of the roller leveller and then moves to the working rolls 10 and 11.

For rotating the working rolls I provide the two large electrical motors 18 which are connected to the trans- 3 missions and gear boxes 19 and the plurality of longitudinally extending wobbler shafts 26. Each of the wobbler shafts 20 drives one of the working rolls 10 or 1.1 in the conventional manner and it may also be convenient to provide means in the gear boxes 19 to absorb any shockloads resulting from leveling operationsk thereby protecting the motors and other appurtenant equipment. In addition, it is desirable that the electric motors 18 be mechanically or electrically interconnected by means, not shown, in order that they always rotate at the same speed.

It is noted in Figure l of the drawing that the working rolls are of considerable length and of small diameter and therefore must be supported against vertical deection during rolling operations. In the present instance the lower working rolls 10 arel provided with a plurality of axially aligned but transversely spaced backup rlls21 along thek length thereof. Eachr of the backup rolls 21 is journaled on both ends in an upturned U- shaped cradle 22 which is rigidly secured to a lower portion 23 of the roller leveler housing 12 by means of a pair. of large bolts 24. The' back-up rolls 21 are oset with respect to the` lower working rolls in a nesting arrangement whereby mostof the back-up rolls partially support a pair. of the working rolls.

The upper working rolls 11 are supported against deiiection during working of metal sheets or strips in much the samel manner by the axially aligned but transversely spaced back-up rolls 26. The back-up rolls 26'are journaled in cradles 27 with each of the cradles 27 being spring mounted by a pair of coil springs 28 and bolt assemblies 29 from an upper portion 30 of the roller leveler housing 12. The arrangement is such that means, such as the hand-wheels 31 or a screw-down motor 32, may beprovided for adjusting the relative vertical position of the upper working rolls 11 to accommodate difierent sizes of stock and different operating conditions.

Although the foregoing is a description of a roller leveler which has been found particularly well adapted for such operations, there. are serious problems encountered due to the downward bending of the upper working rolls under their own weight when the roller leveler is not working material. It is apparent that this condition becomes more aggravated as the length of the upper working rolls increases or the diameter thereof decreases. In addition, this downward bending is most noticeable in the middle of the working rolls. To cornpensate for this deiiection, I provide a series of back-up rolls 33, intermediate the lengths of the upper working rolls 11, which are equipped with magnetic means kas will be hereinafter more fully described.

Rotatably mounted in a cradle 34 is a spindle 35 which carries a pair of magnetic assemblies 36. As shown in the drawing, each of the magnetic assemblies consists of a pair of annular magnets 37 separated by suitable insulation 33 and held in position by the collars 39 which are keyed to the spindle 35. The arrangement is such that the path of magneticilux from one magnet 37 to the other is through the upper working roll 11. Itis contemplated that the attractive force of the magnetic assemblies 36 will be just enough to compensate for the downward sagging of the upper working rolls.

Since the diameter of the assemblies 36 is greater than the rest of the upper back-up rolls 26, I prefer that the magnetic assemblies will be staggered to permit nesting thereof between the upper working rolls 11. As an example, two such assemblies may be mounted on one spindle 3S near the end portions thereof while the next spindle holds only one such assembly in the middle thereof which is out of interfering relation with the other pair of magnetic assemblies.

Although in the illustrated embodiment of the invention I have shown and described a specific roller leveler, it is apparent that the concept of using magnetic backup means may be applied to other types of roller levelers.

As an example, in some cases it has been found expedient to use ay continuous back-up roll which is the same length as the working roll and, in this case, similar magnetic assemblies might be provided along the length of the back-up roll. The magnetic assemblies shown in the invention comprise permanent magnets but electro-magnets arranged in somewhat the same manner could accomplish the same purpose.

Thus, I have accomplished the objects initially set forth by providing an improved roller leveler utilizing magnetic back-up means for the upper working rolls that substantially eliminates the bending of the upper Working rolls when the material being worked is removed. In this manner initial loading of the apparatus is facilitated since the upper working rolls do not block the path of strip travel. This advantage is especially important in high speed operations. In addition, since the upper working rolls are always held against the back-up means, scufling and pitting of the working rolls is substantially eliminated.

As many changes may be made in the size, configuration, and number of elements in the present embodiment, reference should be had to the following appended claims in determining the full scope of the invention.

I claim:

l. In a roller leveler for working sheet and strip stock and the like comprising a frame, elongated relatively small diametered upper and lower working rolls journaled at each end in said frame, said upper and lower working rolls arranged in offset relation to define a sinuous path for said sheet or strip stock, means for driving said rolls, back-up means for said Working rolls, said back-up means including a plurality of cradles mounted on said frame and extending longitudinally thereof, said cradles being positioned in side-by-side relation above and below said upper and lower working rolls, a plurality of spindles iixedly journaled in said cradles, and some of said spindles carrying magnetic means for holding said upper working rolls to prevent sagging thereof under their own weight.

2. Apparatus according to claim 1 further characterized in that each of said magnetic means comprises a -pair of annular magnets separated by insulation, and mounting collars keyed to said some of said spindles thereby holding said magnets in rigid fixed relation on said spindle.

3. In a roller leveler for working sheet or strip stock and the like comprising a frame, upperand lower workingrolls journaled atV each end in said frame, means to drive said working rolls, means to back-up said working rolls including back-up rolls mounted above and below said upper andlower working rolls, means carried by said upper back-up rolls forl preventing the sagging of said upper working rolls, and said last mentioned means comprising permanent magnets having enough attractive force to overcome said sagging.

4. In a roller leveler for working metal sheet or strip stock and theV like comprising a frame, upper and lower working rolls being journaled at each end in said frame, means to drive said working rolls, means positioned intermediate the ends of saidl upper working rolls to prevent the sagging thereof, said last mentioned means comprising a plurality of spindles mounted above said upper working rolls, some of said spindles carrying magnetic assemblies, each of said magnetic assemblies comprising a pair of annular magnets separated by suitable insulation, and means for holding said magnetic assemblies to said spindles.

5. In a roller leveler for working. sheet or strip'v stock and the like and having a plurality of driven thin diametered working rolls, means rotatably supporting said working rolls adjacent the ends thereof, means positioned intermediate the ends of and above at least one of said working rolls to prevent the sagging thereof, and said last mentioned' means comprising magnetic means having enough attractive force to overcome said sagging.

6. Apparatus according to claim 5 further characterized in that said magnetic means comprises a pair of spaced magnets mounted on a spindle, and means mounting said spindle in spaced parallel relation with respect to said one of said working rolls.

7. Apparatus according to claim 5 further characterized in that said magnetic means comprises at least one magnet having a circular outer periphery, and means mounting said magnet for rolling contact with said one of said working rolls.

8. A back-up assembly for the Working rolls of a roller leveler or the like which comprises a spindle, means journaling the ends of said spindle, said spindle being mounted above said working rolls, magnetic means mounted on said spindle, and said magnetic means having a circular outer periphery and adapted to have rolling contact with at least one of said working rolls.

9. Apparatus according to claim S further characterized in that said magnetic means comprises a pair of spaced annular magnets, insulating means separating said magnets, and mounting collars keyed to said spindle on opposite exposed sides of said magnets thereby holding said magnets in rigid xed relation on said spindle.

References Cited in the le of this patent UNITED STATES PATENTS 

